This textbook is intended for undergraduate and graduate students pursuing courses in chemistry and allied fields. It includes fundamental concepts, equations involved in organic reactions, chemical bonds (ionic and covalent bonds), hybridization, representation of a chemical reaction and mechanism of organic reactions. The book also discusses the displacement of bonding electrons involving inductive effect, electromeric effect, mesomeric effect, hyperconjugative effect and resonance. A number of organic reactions involving formation of intermediates such as carbocations, carbanions, free radicals, carbenes, nitrenes and benzynes have also been included. It also discusses different types of reagents involved in a chemical reactions along with types of additional reactions and its detailed mechanism. The book also includes the use of pedagogical elements such as multiple choice questions and end of chapter exercises to aid self-learning among students.